SuperAction類中修飾接口引用為什么要使用protected不用private
public class SupperAction extends ActionSupport implements ServletRequestAware,
ServletResponseAware, ServletContextAware {
private static final long serialVersionUID = 1L;
protected ServletContext context;
protected HttpServletResponse respose;
protected HttpServletRequest request;
protected HttpSession session;
正如上面這些代碼所示，使用protected修飾HttpServletResponse?，HttpServletRequest，HttpServletRequest，?HttpSession 接口引用為受保護屬性，把這幾個接口類的引用設為private（
private?HttpServletResponse ；
private HttpServletRequest；
private HttpServletRequest；
private HttpSession；
）的時候，編譯器會顯示警告，為什么這里屬性不能設為private？
